European Radiology

, Volume 23, Issue 7, pp 1882–1890 | Cite as

Added value of ultrasound re-evaluation for patients with equivocal CT findings of acute appendicitis: a preliminary study

  • Ji Ye Sim
  • Hyuk Jung Kim
  • Jae Woo Yeon
  • Byoung Sun Suh
  • Ki Ho Kim
  • Young Rock Ha
  • So Ya Paik



To prospectively estimate the additional diagnostic value of ultrasound (US) re-evaluation for patients with equivocal computed tomography (CT) findings of acute appendicitis.


Between April 2011 and October 2011, 869 consecutive patients with suspected appendicitis who were referred for CT were included. The likelihood of appendicitis was prospectively categorized into five categories. US re-evaluation was recommended for patients in the ‘equivocal appendix’ and ‘probably not appendicitis’ groups. The overall negative appendectomy rate during the study period was compared with the rate of the previous year, and negative appendectomy rates of the US and non-US evaluation groups were also compared.


Among 869 patients, 71 (8.2 %) had equivocal appendicitis findings and 63 (7.2 %) were diagnosed as probably not appendicitis. The sensitivity and specificity of CT combined with US re-evaluation group (100 % and 98.1 %, respectively) exceeded those of the CT alone group (93 % and 99 %; equivocal group considered as negative appendicitis, 100 % and 89.9 %; as positive, respectively, P < 0.0001). After adding US re-evaluation, the overall negative appendectomy rate in our institution decreased from 3.4 to 2.3 %.


For patients with equivocal CT findings of acute appendicitis, US re-evaluation can improve diagnostic accuracy and decrease the rate of negative appendectomies.

Key Points

Misdiagnosis of appendicitis still occurs, especially in patients with equivocal radiological findings.

The sensitivity and specificity of CT followed by US exceeded those of CT alone.

After US re-evaluation, the negative appendectomy rate decreased from 3.4 to 2.3 %.

US re-evaluation in equivocal cases helps diagnostic confidence and further management.


Appendix Appendicitis Ultrasound Computed tomography Equivocal CT findings 


  1. 1.
    van Randen A, Lameris W, van Es HW et al (2011) A comparison of the accuracy of ultrasound and computed tomography in common diagnoses causing acute abdominal pain. Eur Radiol 21:1535–1545PubMedCrossRefGoogle Scholar
  2. 2.
    Bernard A, Birnbaum M, Stephanie R, Wilson M (2000) Appendicitis at the millennium. Radiology 215:337–348Google Scholar
  3. 3.
    Doria AS, Moineddin R, Kellenberger CJ et al (2006) US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Radiology 241:83–94PubMedCrossRefGoogle Scholar
  4. 4.
    Levine CD, Aizenstein O, Lehavi O, Blachar A (2005) Why we miss the diagnosis of appendicitis of abdominal CT: evaluation of imaging features of appendicitis incorrectly diagnosed on CT. AJR Am J Roentgenol 184:855–859PubMedCrossRefGoogle Scholar
  5. 5.
    Daly CP, Cohan RH, Francis IR, Caoili EM, Ellis JH, Nan B (2005) Incidence of acute appendicitis in patients with equivocal CT findings. AJR Am J Roentgenol 184:1813–1820PubMedCrossRefGoogle Scholar
  6. 6.
    Peck J, Peck A, Peck C (2000) The clinical role of noncontrast helical computed tomography in the diagnosis of acute appendicitis. Am J Surg 180:133–136PubMedCrossRefGoogle Scholar
  7. 7.
    Stroman DL, Bayouth CV, Kuhn JA et al (1999) The role of computed tomography in the diagnosis of acute appendicitis. Am J Surg 178:485–489PubMedCrossRefGoogle Scholar
  8. 8.
    Balthazar EJ, Birnbaum BA, Yee J, Megibow AJ, Roshkow J, Gray C (1994) Acute appendicitis: CT and US correlation in 100 patients. Radiology 190:31–35PubMedGoogle Scholar
  9. 9.
    Balthazar EJ, Megibow AJ, Siegel SE, Birnbaum BA (1991) Appendicitis: prospective evaluation with high-resolution CT. Radiology 180:21–24PubMedGoogle Scholar
  10. 10.
    Weyant MJ, Eachempati SR, Maluccio MA et al (2000) Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis. Surgery 128:145–152PubMedCrossRefGoogle Scholar
  11. 11.
    Webb EM, Wang ZJ, Coakley FV, Poder L, Westphalen AC, Yeh BM (2009) The equivocal appendix at CT: prevalence in a control population. Emerg Radiol 17:57–61PubMedCrossRefGoogle Scholar
  12. 12.
    Kim K, Kim YH, Kim SY et al (2012) Low-dose abdominal CT for evaluating suspected appendicitis. N Engl J Med 366:1596–1605PubMedCrossRefGoogle Scholar
  13. 13.
    Webb EM, Nguyen A, Wang ZJ, Stengel JW, Westphalen AC, Coakley FV (2011) The negative appendectomy rate: who benefits from preoperative CT? AJR Am J Roentgenol 197:861–866PubMedCrossRefGoogle Scholar
  14. 14.
    Choi D, Park H, Lee Y et al (2003) The most useful findings for diagnosing acute appendicitis on contrast–enhanced helical CT. Acta Radiol 44:574–582PubMedGoogle Scholar
  15. 15.
    Pinto Leite N, Pereira JM, Cunha R, Pinto P, Sirlin C (2005) CT evaluation of appendicitis and its complications: imaging techniques and key diagnostic findings. AJR Am J Roentgenol 185:406–417PubMedCrossRefGoogle Scholar
  16. 16.
    van Randen A, Lameris W, van Es HW et al (2010) Profiles of US and CT imaging features with a high probability of appendicitis. Eur Radiol 20:1657–1666PubMedCrossRefGoogle Scholar
  17. 17.
    Rao PM, Rhea JT, Novelline RA et al (1997) Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination. Radiology 202:139–144PubMedGoogle Scholar
  18. 18.
    Garcia K, Hernanz-Schulman M, Bennett DL, Morrow SE, Yu C, Kan JH (2009) Suspected appendicitis in children: diagnostic importance of normal abdominopelvic CT findings with nonvisualized appendix. Radiology 250:531–537PubMedCrossRefGoogle Scholar
  19. 19.
    Nikolaidis P, Hwang CM, Miller FH, Papanicolaou N (2004) The nonvisualized appendix: incidence of acute appendicitis when secondary inflammatory changes are absent. AJR Am J Roentgenol 183:889–892PubMedCrossRefGoogle Scholar
  20. 20.
    Tamburrini S, Brunetti A, Brown M, Sirlin CB, Casola G (2005) CT appearance of the normal appendix in adults. Eur Radiol 15:2096–2103PubMedCrossRefGoogle Scholar
  21. 21.
    Kim HC, Yang DM, Kim SW, Park SJ (2012) Reassessment of CT images to improve diagnostic accuracy in patients with suspected acute appendicitis and an equivocal preoperative CT interpretation. Eur Radiol 22:1178–1185PubMedCrossRefGoogle Scholar
  22. 22.
    Poletti PA, Platon A, De Perrot T et al (2011) Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT. Eur Radiol 21:2558–2566PubMedCrossRefGoogle Scholar
  23. 23.
    Jang KM, Lee K, Kim M-J et al (2010) What is the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after CT? Eur J Radiol 74:71–76PubMedCrossRefGoogle Scholar
  24. 24.
    Anderson SW, Soto JA, Lucey BC et al (2009) Abdominal 64-MDCT for suspected appendicitis: the use of oral and IV contrast material versus IV contrast material only. AJR Am J Roentgenol 193:1282–1288PubMedCrossRefGoogle Scholar
  25. 25.
    Laméris W, van Randen A, van Es HW et al (2009) Imaging strategies for detection of urgent conditions in patients with acute abdominal pain: diagnostic accuracy study. BMJ 338:b2431PubMedCrossRefGoogle Scholar

Copyright information

© European Society of Radiology 2013

Authors and Affiliations

  • Ji Ye Sim
    • 1
  • Hyuk Jung Kim
    • 1
  • Jae Woo Yeon
    • 1
  • Byoung Sun Suh
    • 2
  • Ki Ho Kim
    • 2
  • Young Rock Ha
    • 3
  • So Ya Paik
    • 4
  1. 1.Department of RadiologyDaejin Medical Center Bundang Jesaeng General HospitalSungnam-siRepublic of Korea
  2. 2.Department of SurgeryDaejin Medical Center Bundang Jesaeng General HospitalSungnam-siRepublic of Korea
  3. 3.Department of Emergency MedicineDaejin Medical Center Bundang Jesaeng General HospitalSungnam-siRepublic of Korea
  4. 4.Department of PathologyDaejin Medical Center Bundang Jesaeng General HospitalSungnam-siRepublic of Korea

Personalised recommendations